Though, I'm just enough of a hobbyist linguist to prefer something other than "they, their" (though I use them for convenience, too,) so as not to confuse forms.

despite that many grammarians consider it improper; the gender-neutral singular form use of they and their has been in use for hundreds of years

Yeah, I know, which is kind of both ages, and the blink of an eye in terms of language evolution. It's filling a needed linguistic niche. (Like "ain't" does. As far as I'm concerned, that's a word now.)

it will be much more easily adopted than a new third, non-gendered pronoun. plus. you is already singular and plural, so it wouldn't exactly be unprecedented to allow they to have a singular form._________________FormerlyGreen_Finn